The present invention relates to a method of producing a thin film magnetic head, and more particularly to a method of producing a thin film magnetic head having a narrow track width and a small gap depth adapted to high-density recording and reproducing.
According to the conventional methods of producing thin film magnetic heads, the heads have been produced so that the crush resistance will not be lost even in the case of a small gap depth as is disclosed in Japanese Patent Laid-Open No. 258715/1985 and Japanese Patent Laid-Open No. 32212/1986.
In recent years, however, the thin film magnetic heads have been so designed as to achieve higher density recording and reproducing than those of the conventional art. In the conventional technology, much attention has not been given to forming narrow track widths maintaining high precision or to forming small gap depths, that are essential for achieving the above object.
In the conventional method of producing thin film magnetic heads, the track width and its precision are determined by the photoresist pattern at the time of forming an upper magnetic material of the thin film magnetic head. That is, in forming a photoresist pattern to form the upper magnetic material, if the thickness of the photoresist film is selected to be 3 to 4 .mu.m and the height of the upper magnetic material from the gap layer to be 10 to 12 .mu.m, the thickness of the photoresist film becomes 13 to 16 .mu.m near the lower tapered edge of an organic insulating layer that forms a step with respect to the gap layer, i.e., near a portion that determines the track width, making it difficult to form a track width maintaining precision or to form a track width which is smaller than the thickness of the resist film. According to the conventional technology, therefore, attention has not been given to forming a track width maintaining high precision, forming a narrow track width or forming a small gap width. Furthermore, due to the step caused by forming a thick organic insulating film, the upper magnetic material that determines the track width cannot be formed so precisely.